Fitting Prosthetic Soft Contact Lenses

Improper patient selection and fitting for prosthetic soft contact lenses may result in patient dissatisfaction, complications, such as hypoxia, and harm to your reputation. Therefore, preventing these outcomes is crucial. Here, I provide action steps on how to do this.

IDENTIFY ELIGIBLE PATIENTS

Patients who stand to benefit the most from prosthetic lenses are those who have anterior segment abnormalities, such as aniridia, congenital or traumatic iris defects, ocular albinism, and photophobia, that cause light sensitivity.^1-6 Additionally, ideal candidates for prosthetic soft lenses may seek cosmetic improvement for corneal scarring or leukocoria or present with therapeutic or neurologic concerns, including migraine, amblyopia, cone-rod dystrophies, and color deficiencies.^1-6

Contraindications to prosthetic soft contact lenses are similar to those of other soft contact lenses and include unmanaged ocular surface disease, severe dry eye disease, active ocular inflammation, and compromised or decompensating corneas.^7-9 Therefore, baseline evaluation and ocular surface disease management are essential for safe, comfortable, and successful long-term wear in reusable contact lenses.⁹

CONDUCT A PRE-FITTING EXAM

Right off the bat, acquire a detailed case history (ie, underlying diagnosis, visual potential, prior ocular trauma or surgery, and the patient’s primary goal for lens wear). Also, assess ocular surface health and corneal integrityto ensure the patient doesn’t have active ocular surface disease and is able to wear a lens comfortably. Optimizing ocular surface health before lens fitting improves lens tolerance and overall success with lens wear.^7-9

Next, obtain precise measurements, including horizontal visible iris diameter and pupil size under ambient and dim illumination, and document any binocular deviation to inform lens design and customization. Also, corneal topography or keratometry can be performed to guide base curve selection and identify corneal irregularities that may affect lens centration or movement.

Finally, acquire slit lamp images that capture iris patterns and limbal ring characteristics, along with bilateral external photography obtained under recommended lighting conditions to document eyelid or globe position, iris color, pupil size, and overall symmetry to further guide lens customization.

CONSIDER FITTING SETS

Trial fitting sets can be invaluable for illustrating different levels of customization, which helps set accurate patient expectations (Figures 1 and 2). As an example, trial lenses can demonstrate cosmetic differences between digital and hand-painted irises and highlight when visual function and cosmesis are not aligned, requiring compromise, such as in the case of a decentered iris necessitating an occluded pupil.

SCRUTINIZE VISUAL POTENTIAL

Be especially mindful of high refractive errors (> ±20.00 D sphere, > ±6.00 D cylinder), irregular corneas, and binocular deviations, as these characteristics may limit visual potential and necessitate additional strategies to optimize visual performance. Piggyback systems may improve optical quality, particularly when irregular astigmatism is present or refractive demands exceed what a single prosthetic soft lens can offer.¹⁰

Train on Insertion and Removal

Training patients on insertion and removal of prosthetic soft contact lenses generally follows the same techniques as standard soft lenses. For large-diameter lenses, insertion can be adapted using methods similar to scleral lenses. A scleral insertion tool can assist with placement, and the addition of a preservative-free artificial tear in the lens bowl can facilitate easier application.

PRESCRIBE SOLUTION USE

These lenses are designed for annual replacement and are not approved for extended wear. Thus, their manufacturers recommend using a multipurpose solution to help maintain lens integrity, ensure comfort, and reduce the risk of complications or fading.Proper storage techniques should be emphasized to patients.

TROUBLESHOOT CHALLENGES

• Color mismatch

To avoid patient misunderstandings or dissatisfaction, educate patients upfront on the manufacturer’s warranty, being mindful that exchange policies differ.

• Preservative-containing drops

Only preservative-free drops should be used while wearing these lenses, as preservatives can build up under the lens, causing irritation.

• Decentration or rotational issues

Fit lenses to confirm lens rotation, and provide the manufacturer with photographs to prevent these issues. Recommended photographs include slit lamp and external images of the lens on-eye, obtained after allowing approximately 30 minutes of settling time to accurately assess lens position, centration, and rotation.

• Pupil size mismatches

Let patients, especially those who have light irises, know upfront that a perfect match is often not possible across lighting conditions, though a compromise can be achieved by averaging mesopic and ambient lighting measurements.

• Ocular asymmetry

This can often be addressed via careful measurements, meticulous documentation, and collaboration with the lens consultant.

• Cosmesis dissatisfaction

Trial lenses help patients make informed decisions about their priorities and set predictable expectations about outcomes. In rare cases in which expectations are not met, ensure the manufacturer’s return and warranty policies have been communicated.

A FITTING OUTCOME

Prosthetic lenses enable us to address both cosmetic concerns and functional vision needs. The steps outlined can ensure satisfactory cosmesis and an appropriate fit.